Mass Effect 3 starts with the Reaper invasion beginning in earnest. All Hell breaks loose, and it's up to Commander Shepard to pull a rabbit out of a hat and somehow win a war against a massive fleet of giant, super-advanced, genocidal machines.
Note: Mass Effect, Mass Effect 2, and Mass Effect 3 will hereafter be referred to as ME1, ME2, and ME3.
I bought ME3 out of a sense of obligation. I played the first two games, so I figured I might as well see how it all ends, even though I was pretty sure it was going to suck. I installed the game (via EA's Origin, which is a damn sight better in its early days than Steam was), started it up, played it...and much to my surprise, I enjoyed it. There is once again a wide variety of weapons and upgrades to find or buy. In fact, there's even more variety than in ME1. The storyline is more believable than ME2's. There are great opportunities to direct the course of the narrative. Fun characters from the previous games return. Big conflicts get resolved (for better or for worse, depending on Shepard's actions). This is what ME2 should have been.
In ME1, getting a new weapon meant dealing more damage or firing more accurately. In ME3, some weapons behave completely differently from the others. For example, the Scorpion is a pistol that shoots mini-grenades. Neat! There sure wasn't anything like that in ME1. Most weapons can now be upgraded with a scope, which actually produces a zoom-in effect when aiming. No weapon upgrade in ME1 changed a weapon's mechanics like that. Additionally, character class no longer restricts Shepard's choice of weapons. However, the classes that rely heavily on abilities need to carry as few weapons as possible, since weapons have weight, and more weight means longer ability cooldown times. It's a nice dynamic that adds depth to the game, letting the player make tradeoffs between firepower and finesse as needed.
My only complaint about the weapons was, again, the use of disposable heatsinks as limited ammunition by another name. Do we really have to ape Halo/Call of Duty/whatever? Really? I already beat this drum in my ME2 review, but I think it bears repeating. They introduced a new gameplay mechanic that conflicts with established lore (and occasionally makes no sense whatsoever) for no discernable reason other than aping the competition. Shameful, EA. The fact that reloading uses the same key as "throw grenade" in ME1 doesn't help, although ME1 is arguably The Real WTF there for using the R key for "throw grenade". WTF were you thinking, Bioware? Fortunately, though, I never found myself short of "ammo", even when using a shotgun, so it wasn't quite as obnoxious as in ME2.
Abilities still don't progress as smoothly as in ME1. You need to save up a bunch of points in order to advance to a new level of an ability. However, there are two more levels for each ability than in ME2, and the abilities seem to have a bit more "punch" than in both previous games, which is definitely a plus. Also, each level above 3 offers two different choices, usually offering a tradeoff between brute force and area of effect or between various extra effects (e.g. increased damage to armor vs. increased damage to shields for grenades).
Melee combat has also been reworked: Shepard now has a "heavy melee" attack, which is a biotically-enhanced punch for biotic characters and a stab with a large blade hastily fabricated by Shepard's omni-tool for other character classes. It takes a second or so to "warm up", but it definitely comes in handy from time to time. Shepard can also grab an enemy on the other side of a short wall and instantly kill them, but I never found an opportunity to do so outside of the scripted event that demonstrates the move.
Enemies are more varied this time, too. The Reaper's ground forces (hideously mutated members of various species) are a lot more varied, both in appearance and combat behavior, than the Collectors, and Cerberus has a nice variety of soldiers, including some particularly obnoxious pricks with impenetrable SWAT-style shields. They're definitely more interesting than ME2's collection of mercenaries differentiated by little more than the color of their armor.
The Paragon/Renegade system also got an overhaul. There are now two scores that affect the player's options: a Morality score and a Reputation score. Reputation basically increases the effects of Shepard's moral position and opens up more opportunities for dialog or missions. Morality, as before, opens up different dialog paths, allowing Shepard to persuade or intimidate people into acting differently. Some actions grant Paragon + Reputation, some grant Renegade + Reputation, and some grant pure Reputation. I think it works a bit better than the more simplistic systems in the previous games. In particular, I think it would have worked quite well in ME2, where killing the thresher maw could have granted pure Reputation instead of a large number of both Paragon and Renegade points, which never really made sense to me. Paragon and Renegade interrupts make a comeback, and I dare say they have a bit more punch this time around. I intended to play as a pure Paragon character (as usual), but there were some Renegade interrupts I just couldn't resist. That's a first. One in particular was the single most satisfying experience of the entire Mass Effect series.
The story is again fairly well-told, and the characters are colorful. The new squad member, James, initially comes off as a meathead lunk better suited to a much less intellectual series, but even he proves to be more complex than meets the eye. One of the main villians is basically a physical embodiment of anime, which annoyed me, but he's a villian, so I got to take it out on him eventually, and it helped distinguish him from the other assorted jerks out to foil Shepard. Depending on your actions, you may encounter characters from the previous games, and they have some impact on the story. It's usually nothing particularly earth-shaking, but it helps flesh out the tale. Only some of them are recruitable, though; most have moved on since ME2. I must say, though, that the decision to have Shepard basically under house arrest for several months between the two games so that members of his team from ME2 have the opportunity to move on seems a bit contrived. At least they explained it with an entire DLC for ME2.
One of the most memorable throwbacks to the previous games involves Conrad Verner (of course). It plays out as a series of increasingly improbable coincidences, and it got a good laugh out of me. It even earned me a war asset (i.e. got me closer to a...better...ending). Oh, Conrad, you priceless idiot...
There are also a few missions that are time-critical, where time is measured by progression through the main mission sequence. If you don't do them before certain other missions, bad things will happen. Fortunately, it's almost always obvious which missions are the time-critical. I only got burned by this once, and that was because I completely forgot about the "mission" in question (it's not an official mission; you just have to meet up with someone on the Citadel). The only consequence was the death of a character I didn't particularly care for anyway. Whatever.
My biggest gripe with the story (okay, second biggest gripe; I'll get to the biggest one later) is the part where it forces you to play though Shepard's PTSD dreams. While escaping Earth, Shepard fails to save a little boy. The kid gets killed by a Reaper. Every so often throughout the main mission sequence, you have to chase this kid in slow motion through a burnt forest. Eventually, the kid catches fire and Shepard wakes up. If it happened just once, that would have been OK. It doesn't. It happens several times. By the end of the game, I wanted to shoot the damn kid. Yes, Shepard failed to save an innocent little kid. I get it. Enough already!
Unfortunately still AWOL is the planetary exploration from ME1. Yes, the Mako's "shopping cart in a bouncy castle" handling was obnoxious, but it made the game world feel big and open. Unlike ME2, there is at least a decent excuse for it now: with the Reapers all over the galaxy, driving a light tank around on a planet's surface isn't particularly wise. The lack of planetary exploration is somewhat compensated for by the scale of the missions. They're still very linear, but that linear path is typically longer, which makes it feel more expansive. The background scenery is also quite well-done, especially in the war-torn urban environments. It gives a sense of the suffering the Reapers have caused, which we didn't see quite as much with the Collectors in ME2 or even the Geth and Sovereign in ME1. It adds emotional impact to the story.
In fact, the game world is even more constrained than in ME2: the only place you can get out and roam about freely is the Citadel. I was surprised to find that this didn't really bother me; again, with the Reapers all over the place, it makes sense that the Citadel would be pretty much the only safe haven left in the galaxy. It also helps that the Citadel is a lot bigger than in ME2.
Fortunately now AWOL is ME2's tedious planet scanning/mining. The Normandy can now emit a scanning pulse that detects everything interesting within its range all at once. The one caveat is that it also gets the attention of nearby Reapers. Get too much attention, and the Reapers will come to investigate, forcing you to flee the system. Scanning finds such goodies as credits, fuel, and war assets.
As icing on the cake, the most egregious bugs from ME2 are fixed. I'm pretty sure the prologue has Shepard drop off ledges several times just to prove that they fixed that damn "stuck floating in midair" bug that was the bane of my existence in ME2. Load times are quite reasonable, and I don't recall the game ever randomly deciding to make loads take a really long time for no reason. On the other hand, it takes a frankly unreasonable amount of time for the main menu to load when the game starts up, apparently because it needs to connect to some server somewhere. Also, the EA logo video at startup consistently gets interrupted by some Origin-related thing. Once the game gets going, though, it's smooth sailing.
Overall, I had a lot of fun with Mass Effect 3.
Then I got to the end. Holy shit. In the last five fucking minutes of gameplay, the story goes completely off the rails and tumbles headlong into the Gorge of Insanity. As soon as I saw that platform rise up into a beam of white light, I thought to myself, "This is going to be stupid, isn't it?" I could not possibly have imagined just how stupid it was about to get. All of a sudden, this game that had been pretty much straight sci-fi starts throwing all this semi-mystical bullshit at me. The tone changes completely. It's like shifting without a clutch. As shitty icing on this shitty cake, the ending also more or less invalidates Shepard's every accomplishment over the course of the entire series. I could rant for hours about this, but I'll keep it short. I honestly can't imagine anybody thinking this ending was good, and I find it quite difficult to believe that this was the best they could do in the time they had: it took me all of about 15 minutes to think up a better set of endings. Thus, I simply cannot ascribe this to incompetence. This has to be intentional trolling. Fuck you, EA.
After playing, I watched the alternative outcomes for the major events in the game on Youtube, and that left me feeling even more disappointed! Specifically, what had been my favorite Renegade interrupt in the entire series turned out to have very little impact on the outcome of the scene. I felt robbed. Again.
In short, Mass Effect 3 is like a pedophile who lures children into his van with promises of candy and then, surprisingly, actually makes good on his promises before the molestation begins. If you liked ME1 or ME2, go ahead and play ME3. If you didn't particularly care for ME2, slog through it anyway so you can have a better ME3 experience. Just watch out for the Bad Touch at the end.